1. Field of the Invention
The present invention relates to an optical disc apparatus and a tracking control method, and is suitably applied to an optical disc apparatus that records information on an optical disc and reproduces the information therefrom, for example.
2. Description of the Related Art
From the past, optical disc apparatuses that record information including videos, music, and various types of data on optical discs such as a Blu-ray Disc (registered trademark, hereinafter referred to as BD), and reproduce the information from the optical discs have been widely used.
Particularly in recent years, an amount of information has been increased by achieving higher definition of videos, higher sound quality of music, and the like, and the number of contents to be recorded on one optical disc is also desired to be increased, which leads to a demand for an increase in a recording capacity of the optical discs.
As the optical discs, there is proposed a so-called multi-layer optical disc in which a plurality of recording layers each having tracks formed in advance are provided and an information amount corresponding to the number of recording layers can be recorded as in a case of the BDs.
Further, as one of optical disc apparatuses that increase a recording capacity of an optical disc, there is also proposed an optical disc apparatus in which a relatively thick, single recording layer is provided on an optical disc, a plurality of layers with recording marks are provided in a thickness direction of the recording layer, and then an information amount corresponding to the plurality of layers is recorded (see, for example, Japanese Patent Application Laid-open No. 2008-135144 (FIG. 12)). In fact, the optical disc and the recording method as described above are also referred to as a volumetric optical disc and a volumetric optical recording method, respectively.